It has been known for many years that flexible plastic hoses can be produced by winding one or more strips or elongated members formed from polymeric materials into a helical structure. Upon winding displaced portions of these strips on adjacent turns of the helix, these adjacent turns, which have been referred to as connecting portions, can then be secured together, such as by the use of polymeric bonding material or hot melt compositions. These molten bonding materials are ordinarily applied to a connecting portion of such a member as it is wound into the helical structure.
Such helically wound flexible hoses, as disclosed for example in Richitelli, U.S. Pat. No. 3,199,541, have included both the use of a single strip-like member with a U-shaped channel on one edge and a projection on the opposite edge, and a two-strip hose produced from a U-shaped channel member and a cap member wound in alternating turns. The Richitelli patent also includes the use of a reinforcing material 38, such as that shown in FIGS. 6-11 thereof, which is said to be substantially stiffer than the other hose materials, and which is arranged on the radially extending walls of the hose. This patent contends that the purpose of same is to provide a stiff reinforcing element between the convolutions of the hose. In some embodiments thereof, the reinforcing material, comprising polyethylene or polyethylene copolymers is extruded and united with the basic strip immediately after the extrusion process, and the reinforcing material is exposed to the surface of the strip so that the bond between adjoining strips may involve bonding of the reinforcing material of one strip to the softer material of an adjoining strip.
Another such strip material is shown in Finley, U.S Pat. No. 4,383,555, in which the strips include a thin web or membrane 21 of relatively soft material and a pair of relatively rigid rib components extending along the opposite margins of that web and co-extruded therewith.
Yet another flexible hose is shown in Eichelberger et al, U.S. Pat. No. 4,531,551, which discloses a flexible hose having smooth inner and outer wall surfaces instead of the undulatory outside contours presented by hoses including U-shaped members and the like. The hose in Eichelberger et al is thus prepared from S-shaped individual co-extrusions in the embodiment shown in FIGS. 1 and 2 thereof, and includes reinforcements disposed in the space between the double wall construction thus providing a material harder than the walls.
Additional flexible hoses are shown in Dillon, U.S. Pat. No. 4,420,019, which discloses a channel and cap construction in which the cap is formed of a relatively rigid material, and the channel is formed from a relatively soft material, with the cap being filled with bonding material.
Cothran, U.S. Pat. No. 4,291,728, shows in FIG. 3 thereof a spirally wound hose whose convolutions include U-shaped portions and are interlocked so that lips 33 on each convolution extend into the U-shaped portion of the adjoining convolution, and in which each such convolution is provided with a projecting portion 5a abutting lip 33a of the adjoining convolution to define a substantially smooth interior wall within the hose.
Carlson et al, U.S. Pat. No. 4,337,800, discloses yet another extruded flexible hose whose channel sections have flanges 14 abutting one another when the hose is in a straight condition, and strips 30 of a harder material at the outboard ends of the flanges.
U.S. Pat. No. 4,589,448 of del Valle shows yet another channel and cap construction in which the cap of the spirally wound hose has a hinge section 24 which is thinner than the remainder of the cap, and which is preferably formed from a polymer which is harder than the remainder of the cap, such as a hard polypropylene.
Finally, in co-pending application Ser. No. 938,551, applicant's assignee has discovered that such spirally wound hoses can be produced with enhanced structural strength and integrity, and still remain readily bondable by fusing a buffer material which is more readily susceptible to fusion under heat and/or pressure to a structural material which is a relatively difficult to fuse polymeric material having greater strength and rigidity. Molten polymeric bonding material can then be used to bond these buffer materials together.